Although emerging adults (EA, aged 18-25) account for approximately one-fifth of all publicly funded treatment episodes, we know very little about whether existing alcohol treatments are developmentally appropriate. Most of our knowledge about alcohol interventions for this age group is from studies in college settings, but according to the National Survey on Drug Use and Health, only 53% of emerging adults with Alcohol Use Disorders (AUD) are in college. Treatments that alter social networks may be especially promising for emerging adults, because alcohol and drug-free social opportunities may be particularly scarce during this developmental period. To address these problems, Dr. Smith will develop and pilot test a Peer-Enhanced Community Reinforcement Approach (PE-CRA) intervention, in which close friends of emerging adults receiving publicly funded AUD treatments will attend therapy sessions. This application requests funds to provide the mentoring needed for Dr. Smith, an experienced clinician, to develop and investigate the efficacy of the proposed PE-CRA intervention. Dr. Smith will receive mentoring from two senior health services researchers, Drs Michael Dennis (primary) and Mark Godley (co-mentor), that focuses on knowledge gains in advanced data analytic skills for health services research (i.e., propensity score matching, methods for dealing missing data, analysis of moderators and mediators), clinical research designs and study implementation, knowledge about the EA period of development. Support from the K23 mechanism will relieve Dr. Smith from teaching duties and allow him to dedicate 75% effort toward developing this line of research. His other 25% effort will be dedicated to teaching addictions coursework to social workers. It is anticipated that Dr. Smith will secure independent research funding for further studies that improve our understanding of what characteristics of EA mediate treatment effectiveness.